VIDEO: Challenges in diagnosing, managing polymyalgia rheumatica

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Hi, I am Sebastian Sattui. I'm an assistant professor in the Division of Rheumatology and Clinical Immunology at the University of Pittsburgh and it's my pleasure to tackle these and some other questions on polymyalgia rheumatica or PMR. There are several challenges with regards to the diagnosis of PMR. I think PMR, as much as it can be presented in a very classical way, right, so we usually see it in a patient over the age of 50, particularly peak incidences between 70 and 80, who presents with shoulder and pelvic girdle, so proximal pain and particularly stiffness associated with decreasing immobility, can also present with some kind of constitutional symptoms and that's usually the classical way that we expect PMR to see the patient receive kind of the dose of steroids between 15 and 25 and they feel wonderful and magical and they're running around everywhere. However, if you know, that's not necessarily the case for a lot of patients with PMR and there's several challenges around the diagnosis.

I think particularly, one, is that yes, we expect the classical PMR presentation, but we know that in a significant proportion of patients, that's not necessarily the case. PMR mimickers are something always very specific to take into account because a lot of different conditions or patients can present with either constitutional symptoms like low-grade fever, like shoulder pain and patients who have a history of other mechanical reasons for shoulder pain, a rotator cuff, arthritis, that can present with the symptoms that maybe are not responsive to steroids. So frequency of mimickers is a very common challenge in the diagnosis of PMR.

I already mentioned some kind of mechanical causes of either shoulder or hip symptoms, such as, again, rotator cuff tendinopathy in the shoulders, gluteal tendinopathy, osteoarthritis as well. There's some other inflammatory conditions that can present as well, similar to PMR, and that can be laid on and that can be rheumatoid arthritis and there's some specific features that need to be taken into account, such as, of course, the presence of positive serologies, cirrhosis disease, late onset lupus or late onset axial spondylarthritis  can also present in such way, GCA, which I'll elaborate I guess in one of the other questions, is also something to always take into account, but also endocrine conditions, such as hypothyroidism can present with a clinical presentation resembling PMR. Malignancy is always something to take into account, particularly in this age group, as well as infections and we usually don't necessarily suspect this, but subacute endocarditis can also be a common mimicker of PMR.

The other challenge with PMR is that we don't have any specific tests for this diagnosis, unlike some of our other conditions, although none are flawless, but serologies such as rheumatoid factor or CCP antibodies in RA or other serologies in other conditions or even biopsies, that's not something that we have in PMR and that also kind of adds another layer of complexity to the diagnosis of a patient that does not necessarily present in a classical way or does not have that typical response that we would initially expect to. Inflammatory markers, which are usually kind of go-to lab tests for some of these patients can be both sedimentation rate and C reactive protein normal in a percentage of these patients, so there is certainly kind of a need there, although they are some emerging literature about different imaging studies such as ultrasound, MRI or even PET scans. These are still kind of not really employed as much as we would want to in clinical practice, particularly MRI and PET scan, so that's another kind of challenge.

A third challenge is as much as we always expect, that is true, again for a lot of patients with PMR, this kind of magical response to glucocorticoids, the fact is that not every single patient responds as would be expected, which does not necessarily mean that the pill goes in and the patient is now completely symptom-free, so a little bit of delay in some relief can happen in some patients, but most importantly what we always should remember is that a lot of things get better with glucocorticoids. [The] reason why this was not actually included in the 2012 classification criteria because the lack of specificity, so that's another point and a final layer to the challenges in polymyalgia rheumatica diagnosis is that as much as this is systemic rheumatic condition, it's an inflammatory condition, a lot of those patients do not get diagnosed in the specialty setting and although there are probably a lot of non-specialists who are very keen to the diagnosis of PMR, who might have experience.

This is not the case probably for the majority of them and the fact is, especially those challenging cases, those not necessarily like classical cases, who get to specialty elevation, already on glucocorticoid, delayed to specialty care can be quite challenging as well and this, I'll say, as much as of course a lot of this takes into having seen the patients' experience with this, it also kind of reflects a little bit in how there's a need for better clinical care pathways for these patients, particularly those who have quote unquote atypical features and how we need to better educate, not only our colleagues, and also build referral pathways for these patients to be assessed.